JPS595760B2 - How to fasten elements to drilled holes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for anchoring various elements in a borehole.

The method according to the invention adheres the elements to the activated binder mixture very reliably, and since the activated binder mixture can be produced homogeneously, it is always activated in the same way. This method can be used.

Two main methods are used to bury and secure elements such as reinforcing bolts in tunneling and mining sites.

The first method is a mechanical fastening method, which is characterized by expansion of parts of the element in different directions during the fastening operation.

Methods using special elements that expand in conjunction with the fixation of the main element or that expand independently of the fixation of the main element (the main element can be fixed to the special expanding element in various ways) also fall within this scope. included.

In the mechanical fixation method, a special element or a part of the main element presses into the surrounding material such as the rock that will form the hole, and is fixed to the part by the frictional force between the special element or the main element and the surrounding material. Retained.

Another method serving the above purpose is called chemical fixation method.

In this method of fixation, a more or less viscous or plastic chemical is applied in various ways to almost completely fill and surround the borehole insert of the element.

As the chemical solidifies through a chemical reaction, a hardened body is formed between the surrounding material and the element inserted into the surrounding material, thereby holding the element together.

Then, adhesive forces of the chemical substance that actively contribute to holding the element are formed between the chemical substance and the element and between the chemical substance and surrounding substances.

Even in this case, two methods can be distinguished.

One is a method in which the chemical substance formed contains a binder consisting of an inorganic substance, and the other is a method in which the chemical substance formed contains a binder consisting of an organic substance.

In addition, the mechanical fixing method is sometimes used in combination with the chemical fixing method, and especially when cement mortar is used, the chemical fixing method is used in combination with the mechanical fixing method.

Traditionally, when mechanically embedding and fixing elements in a drilled hole,
It is known that the reliability of the frictional force generated between the element and surrounding materials is extremely low.

This type of embedding method allows the element to undergo gradual elongation (creep) when subjected to large stresses, long-term stresses, or both at the same time.
) There is a risk of

To eliminate these drawbacks, mechanical bonding methods are used in combination with chemical bonding methods.

In such cases, cement certal injection means are generally used.

With this injection method, the mortar used must have a relatively low viscosity, but it is nevertheless necessary to check how much of the element inserted into the drilled hole is actually embedded. It cannot be inserted while

Attempts to overcome the problems described above have been made by relying entirely on chemical methods.

However, means other than injection methods are used in connection with the chemical method.

That is, the binder material was contained in a cartridge and introduced into the borehole.

Several methods have been developed for inorganic binder materials, in which the inorganic binder and filler are formed at the construction site with an activating liquid (usually water). Fill the cartridge with mortar, insert the cartridge into the borehole, and then insert the element into the borehole.

The mortar in the cartridge is thereby forced out of the cartridge and fills the space between the element and the surrounding material.

This method is not completely uncontroversial.

The main reason for this is that the process of putting mortar into the cartridge is difficult.

However, conventionally proposed methods solve this problem by using ampoule-like containers made of brittle materials.

That is, an ampoule-shaped container containing water is inserted into a cartridge filled with a binder and a filler.

Then, when the cartridge is inserted into the borehole and then the fixing element is inserted into the cartridge, the container member containing water is crushed and the cartridge is also crushed.

The released binder mixture and water are thus mixed by the rotatingly pushed element.

However, this method has major flaws. That is, the mortar that bonds the element to the surrounding material cannot be properly mixed and prepared.

If the mixing action is insufficient, some parts of the binder will not be supplied with water at all, while other parts will be supplied with too much water.

Unless some part of the binder is utilized at all. The bonding strength of the intended element is reduced, and the reacted mortar also receives additional water, reducing its strength.

Other methods have been proposed in which organic substances such as synthetic resins are used as binders.

In this method, too, a cartridge is used in which the adhesive substance is retained until the cartridge is crushed by the invading part of the element to be secured.

This type of method differs essentially in the construction of the cartridge containing the binder material.

Generally, when a synthetic resin is used as a binder, it is necessary to add a curing agent to the adhesive.

According to other proposals, the hardening agent is placed next to the main substance in the center of the cartridge, or the hardening agent is placed so as to surround the adhesive.

Also, according to some methods, the curing agent and binder are separated by some type of membrane.

According to another method, the curing agent and the binder are made to react with each other at the interface of both materials.

Regardless of the different configurations of the cartridges, the curing agent and the synthetic resin can still be mixed by rotating the element into the borehole.

Also, in this method, the quality of the mixture of curing agent and binder cannot be adjusted to the intended optimum bonding strength.

Moreover, such cartridges are expensive and, in addition, have a relatively short shelf life.

This can be said to be particularly short in the case of cartridges in which no special membrane is arranged between the synthetic resin and the curing agent.

According to the invention, an IJ acetate is used containing a binder mixture optionally containing a filler selected from fine sand silica ash, fly ash.

The car) IJ joint is preferably molded into a cylindrical shape with both ends sealed.

The binder consists of one or more hydrocurable ones of Portland cement, alumina cement, and Keene's cement, but other types of binders may be used, or it consists of a mixture of various binders described below. It can be anything.

The casing, which is a component of the cartridge, is made of a liquid-permeable material, such as moisture-proof paper, perforated plastic sheet, or similar materials.

Such materials are impermeable to the binder mixture within the casing.

Additionally, the cartridge should be rigid to facilitate handling during immersion in the active liquid and during insertion into the drilled hole.

This is accomplished by providing the cartridge with a stiffening member made of a rigid, brittle material.

Such a stiffening member should be made of a material having rigidity and brittleness, such as a synthetic resin material such as non-soft styrene resin, or glass.

A stiffening member made of such a material is formed by weaving the material into a mesh or by casting it into a cylindrical shape.

Furthermore, by knitting and connecting rings of the above-mentioned materials, it may be made into a vertically long rod-like object.

The stiffening member thus obtained can be disposed so as to surround the entire or part of the outer periphery of the casing.

Alternatively, the stiffening member may be arranged inside the casing.

When arranged inside the casing, the stiffening member can be formed and arranged in various different structures and shapes.

For example, the stiffening element can be arranged to surround the binder mixture, or it can be arranged such that the stiffening element is embedded within the binder mixture.

In such a case, it is not necessary to have a cylindrical shape, and the cross section may be arcuate and longitudinally long.

Alternatively, the stiffening member may be integrated with the casing.

In such a case, the stiffening member may constitute a part of the casing, or the casing itself may be the stiffening member.

A cartridge provided with said stiffening element is highly suitable for use in inserting an activated binder mixture into a borehole.

The cartridge configured as described above is used when embedding elements in accordance with the above-mentioned purpose.

If the bond housed therein is comprised of a hydrocurable adhesive mixture, the cartridge may be immersed in an activating solution, i.e., water.
Immerse for 0 seconds or more.

During this immersion, the activating liquid is absorbed into the binder mixture of the cartridge.

After the soaking time, the cartridge is removed from the activation liquid.

The desired number of cartridges thus treated are inserted into the borehole.

Then, when the element is inserted into the borehole, the activated binder mixture is forced out of the cartridge, breaking or yielding the stiffening member and with it the casing.

There is no need to stir and mix the binder mixture extruded from the cartridge.

This is because sufficient activating liquid necessary for bonding is present and absorbed in all parts of the cartridge.

Therefore, the element does not have to be rotated while being inserted into the borehole in order to mix the binder material and the activating liquid, as is the case in the past.

Thus, even without rotation, the element inserted into the borehole is completely surrounded by activated bonding material with sufficient bonding strength.

The binder mixture is an accelerating agent.
, Retarding agent, Corrosion inhibitor,
An antifreeze agent or a mixture thereof may be included as appropriate.

In other cases, the binder mixture includes an expanding agent such as calcium sulfoaluminate or aluminum powder capable of generating gas to expand the binder mixture, and further strengthens and stabilizes the binder mixture. is fixed.

The above-mentioned quick setting agents, slow setting agents, corrosion inhibitors, and antifreeze agents may be absorbed into the binder mixture together with the activating liquid.

In such a case, it is effective to include each side in the activation liquid as necessary.

When using a particular binder mixture for a particular purpose, the hydrophobic material may be incorporated into the plastic material.

The present invention provides a simple method for inserting and securing elements into the surrounding material of the rock, concrete, or structure forming the borehole.

This method is a simple and reliable method for fixing elements that overcomes the weak fixing force of conventional methods.

Furthermore, the method of the present invention provides flexibility in terms of operation and processing time not available with previously proposed methods.

When inserting and fixing an element, or if a load is to be applied to the element later, that is, if the element is simply embedded,
Cartridges are used for this purpose that adhere with a short curing time.

On the other hand, cartridges with moderate to long curing times may be used for primary bonding.

If the load is to be applied immediately after the elements are bonded, sufficient bonding strength can be quickly achieved by adding one or more drops of quick setting agent.

In some cases, it may be worthwhile to increase the initial bonding time so that greater bond strength is achieved rapidly.

In such a case, the blending ratio of the quick-setting agent and the slow-setting agent may be adjusted.

Furthermore, a large number of different additives can be absorbed into the binder together with the activating liquid, thereby minimizing as much as possible the type and number of cartridges required to meet the various needs occurring on construction sites. can do.

EXAMPLE A cartridge was fabricated having a mixture of hydrocurable binder, fine sand, rapid binder, and a liquid-permeable casing of moisture-resistant paper.

The cartridge has a cover made of a stiffening net made of a rigid but brittle synthetic resin material;
It is 200 tons.

A hole with a diameter of 32 mm was drilled in order to bury the cam steel material with a diameter of 20 mm.

Add 5 cartridges to activating liquid (water in this case) for 30 min.
The entire body was immersed for ~45 seconds before being inserted into the borehole.

When the cam steel was then inserted into the drilled hole, the mortar formed by the hydrocurable binder mixture and activating liquid broke the cage of the cartridge and was forced out of the cartridge.

This mortar filled the space between the borehole wall and the cam steel.

The buried length was approximately 900+++x. After 2.3 hours, increasing tensile forces were applied until the cam steel broke.

The tensile force when the cam steel material broke was 13.5).

This corresponds to a breaking load of approximately 1.5 tons/m for buried bolts.

Claims (1)

[Scope of Claims] 1. In a method for fixing a part of an element to a drilled hole in rock or concrete, when a cartridge containing a binder mixture is introduced into the drilled hole, before the cartridge is inserted into the drilled hole. ni, 3
The element is immersed in the activating liquid for more than 0 seconds to allow the activating liquid to pass through the casing of the cartridge and penetrate into the binder mixture sufficiently uniformly, and then when the element is inserted into the drilled hole, the inside of the cartridge is A method for fixing an element in a borehole, characterized in that the activated binder mixture is forced out of the casing without destroying or yielding the stiffening elements which together with the casing constitute the cartridge. 2. The binder mixture comprises one or more water-based adhesives selected from Portland cement, alumina cement, Keens cement, and a filler selected from fine sand, silica ash fly ash. A method of securing an element according to claim 1 in a borehole. 3. The activating liquid that immerses the cartridge and enters the binder mixture in the casing, which is a component of the cartridge, contains an activator, an accelerating agent, a setting slowing agent, an antifreeze agent, a plasticizer, and a hydrophobizing agent. A method for fixing an element in a drilled hole according to claim 1, characterized in that it contains one or more kinds of additives. 4. The cartridge comprises a casing that surrounds the binder mixture and is permeable to the activating liquid but impermeable to the binder mixture, and a stiffening member that ruptures or yields when the element is inserted into the borehole. A method for fixing an element according to claims 1 to 3 in a drilled hole. 5. The method of fixing an element to a borehole according to claim 4, wherein the casing, which is a member constituting the cartridge, is made of moisture-resistant paper or a porous plastic sheet. 6 The binder mixture may contain an accelerating agent, a slowing agent, an antifreeze agent,
5. A method for fixing an element in a drilled hole according to claim 4, which comprises one or more additives selected from among a plasticizer, a hydrophobizing agent, and a swelling agent. 7. A method of fixing an element in a drilled hole according to claim 6, characterized in that the binder mixture contains enough of the swelling agent to compensate for the shrinkage that begins during curing of the binder mixture and to swell it. . 8. The method of claim 7, wherein the swelling agent is calcium sulfoaluminate. 9. The method of claim 4, wherein the binder mixture includes aluminum powder which generates gas and expands the binder mixture.